DAVENPORT, Iowa (AP) — Officials battling the spread of a destructive beetle in Iowa have quarantined firewood and ash products moving within 25 counties in the eastern part of the state.

The state Department of Agriculture and Land Stewardship announced the regional quarantine Friday. It’s aimed at preventing the spread of emerald ash borer, which has been confirmed in four eastern Iowa counties.

The move means firewood and ash products cannot be moved from one of the quarantined counties unless permitted by state regulators. Officials say most infestations have been started by people accidentally moving infested firewood, nursery plants or sawmill logs.

An infestation of emerald ash borer was first detected in an Iowa county in May 2010. Three additional counties have been declared infested in 2013.